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An IPsec reference implementation for Linux.
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IPSec VPN configuration information.
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Counterpane Systems has exposed insecurities in Microsoft's Point to Point Tunneling Protocol.
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Linux, FreeBSD and NetBSD client for the proprietary Microsoft Point-to-Point Tunneling Protocol, PPTP.
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Point-to-point tunnelling protocol server for linux. Allows Linux machines to operate PPTP VPNs with Windows 2000 machines.
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An IETF group working on PPP's extensions.
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PPTP technical specification by 3Com.
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A GNU program allowing to encrypt arbitrary TCP connections inside Secure Sockets Layer (SSL).
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Technologies used for creating secure VPNs. Various standards and protocols listed with links to related RFCs.
